This invention relates to a transmission arrangement for a vehicle and more particularly to an improved engine transmission arrangement for driving a motor vehicle.
As is well known, it has been proposed to provide transverse engine placement in vehicles to provide a more compact engine compartment and power arrangement. Although the transverse engine placement has a number of advantages, it also presents certain problems in connection with layout of the drive train. A type of engine and transmission arrangement that has high utility is disclosed in copending application entitled "Engine Unit For Vehicle", Ser. No. 270,357, filed Nov. 14, 1988, now U.S. Pat. No. 5,024,287, in the name of Karou Okui and assigned to the Assignee of this application. In the arrangement shown in that application, there is provided an in line engine in which the engine output shaft drives an auxiliary shaft which, in turn, drives the valve train and a transmission for powering the vehicle. Such an arrangement provides a very effective and compact power unit.
In order to improve the performance of an engine while maintaining a small size, it is well known to run the engine at higher engine speeds. At higher engine speeds, a greater power can be attained for a given displacement. However, in many instances, it is desirable to employ a transmission that includes either a fluid coupling or a torque converter so as to provide automatic gear selection. Most torque converters or fluid couplings are designed so as to operate at relatively low maximum engine speeds. Therefore, existing fluid couplings and torque converters cannot be utilized practically in connection with engines having high engine speed.
Also, if the torque converter or fluid coupling is to be driven at a high engine speed, then the size of the torque converter can become quite large and make compact arrangement more difficult.
It is, therefore, a principal object of this invention to provide an improved transmission arrangement for an internal combustion engine which is compact and which nevertheless permits the use of a fluid coupling that can be small in size without restricting the engine speed.
It is a further object of this invention to provide an improved arrangement for driving a fluid coupling from an engine through a reduction train which will insure that the design speed for the coupling is not exceeded regardless of the engine speed.